GB2255204A

GB2255204A - Elevator apparatus.

Info

Publication number: GB2255204A
Application number: GB9208375A
Authority: GB
Inventors: Yoshio Sakai; Yoichi Ono
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 1991-04-26
Filing date: 1992-04-16
Publication date: 1992-10-28
Anticipated expiration: 2012-04-16
Also published as: JP2917182B2; CN1045187C; SG18295G; GB2255204B; GB9208375D0; CN1066040A; HK31095A; JPH05208788A

Abstract

In an elevator apparatus, by use of a microcomputer (1), a signal is supplied to a base driving circuit (5) so as to turn driving control elements on/off to generate a pulse-width controlled voltage to thereby control the rotation of a door driving motor. An elevator stoppage signal and a door opening/closing allowing signal (8) are supplied from an elevator control means (9) to the microcomputer (1) and the base driving circuit (5). The base driving circuit (5) has a double system for its door opening operation so that it should not perform the driving of opening a door when the signal (8) shows the fact that the elevator is not in stoppage and the location is outside the zone in which the opening/closing of the door is to be allowed. <IMAGE>

Description

ELEVATOR APPARATUS The present invention generally relates to an elevator apparatus, and particularly relates to an apparatus for controlling the opening and closing of a door of an elevator. More particularly, the present invention relates to an elevator door control apparatus in which an elevator door can be controlled safely so that the door is not opened in running of the elevator as well as outside a zone in which the opening/closing of the door is allowed.

As a conventional elevator door control apparatus, known is that using a DC motor, and driving elements for driving an elevator door in the opening and closing directions respectively. According to this technique, the door opening/closing is controlled by controlling the time width of current conduction to be supplied to each of the respective driving elements in the door opening and closing directions which are driven alternately with a predetermined period.

The most important condition to be obeyed by an elevator door control apparatus is that an elevator door must not perform an opening operation at all in running of the elevator as well as outside a zone in which the opening/closing of the door is allowed. In addition, it is a necessary condition for an elevator door control apparatus that the door holding force in the closing direction is kept to be not less than a predetermined value so that passengers cannot get out of a cage thoughtlessly in case when an elevator is temporarily stopped, for example, by a fault or the like, at an intermediate position between adjacent floors and outside a zone in which the opening/closing of the door is allowed, while the door holding force must not be excessive more than a certain level so that the passengers closed in the cage can be saved from the outside.

According to the above-mentioned conventional technique, when an elevator is in running and is outside the zone in which the opening/closing of the door is allowed, a current is supplied to the driving elements in the closing direction with a predetermined time width to thereby keep on giving a door closing force about a quarter of that necessary at the time of the door closing operation, and at the same time, the driving elements in the opening direction are brought into its OFF state perfectly to make a door driving motor not be driven in the opening direction, so that the above-mentioned conditions are satisfied to make it possible to perform the door opening and closing control safely.

In the above-mentioned conventional technique, however, for example, in the case where abnormality arises in a microcomputer which controls the driving elements in the opening and closing directions to thereby cause such a trouble that the microcomputer gives a command to make the driving elements in the opening direction conductive fully, there occurs a problem that the door may be driven in the opening direction.

As a conventional technique relating to an elevator door control apparatus in which such a problem as mentioned above can be solved, known is a technique as disclosed, for example, in JP-A-58-224983.

According to this conventional technique, a contact which is kept opened in running of a cage is connected in series to an opening driving elements for driving a door in the opening direction. Thus, in running of the cage, the contact is made OFF and only a current in the door closing direction is supplied to a motor so that not only a door closing force is kept but the door is prevented from being opened.

In this conventional technique, however, since the above-mentioned contact is provided on the cage so as to be driven under the control through a signal line from an elevator control apparatus provided in a machine room, it is necessary to additionally provide a signal line between the machine room and the cage.

In the above-mentioned conventional technique, there has been a further problem that since a control apparatus for an elevator door driving motor does not have sufficient reliability, it is necessary to additionally provide a countermeasure such as a contact in a main circuit.

Embodiments of the present invention may provide an elevator door control apparatus in which the reliability thereof can be improved by a simple configuration.

In addressing the above problems, the elevator apparatus according to an aspect of the present invention may comprise: an electric motor for driving a door of an elevator; semiconductor control elements for controlling electric power to be supplied to the motor; a driving circuit for generating a control signal to be supplied to the semiconductor control elements, on the basis of a door opening/closing command from an elevator control means; and means for preventing a control signal for opening the door from being supplied from the driving circuit to the semiconductor control elements, in accordance with a predetermined signal supplied from the elevator control means.

According to another aspect of the present invention, the elevator apparatus may comprise: an electric motor for driving a door of an elevator; semiconductor control elements connected between a DC power supply and the motor without interposition of any mechanical circuit-opening/closing means and for controlling electric power supplied to the motor; a pattern generating means for generating an on-off pattern for the semiconductor control elements on the basis of a door opening/closing command from an elevator control means; a driving circuit supplied with the on-off pattern and for generating a control signal to be supplied to the semiconductor control elements; and means for preventing respective outputs of the on-off pattern for opening the door and the control signal for opening the door, in accordance with a predetermined signal for forbidding the opening of the door supplied from the elevator control means.

According to such configurations, it is sure and possible to prevent a control signal for opening a door of an elevator from being supplied to the abovementioned semiconductor elements to thereby forbid the opening of the door, on the basis of a signal for forbidding the opening of the door in the case where opening the door is dangerous, for example, the elevator is in running or when the elevator is stopping outside the zone in which the opening/closing of the door is allowed.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which: Figs. 1A, 1B and 1C are block diagrams illustrating the whole configuration of an embodiment of the present invention; Fig. 2 is a block diagram illustrating the configuration of part of an elevator control apparatus and a door control circuit, relating to the present invention; Fig. 3 is a block diagram illustrating the configuration of a base driving circuit according to the embodiment of the present invention; Figs. 4A, 4B and 4C are block diagrams illustrating the whole configuration of another embodiment of the present invention; and Fig. 5 is a block diagram illustrating the configuration of a base driving circuit according to the other embodiment of the present invention.

Referring to the drawings, embodiments of the elevator door control apparatus according to the present invention will be described in detail hereunder.

Figs. lA, 1B and 1C are block diagrams illustrating the whole configuration of one embodiment of the present invention, Fig. 2 is a block diagram illustrating the configuration of part of an elevator control apparatus and a door control circuit, relating to the present invention, and Fig. 3 is a block diagram illustrating the configuration of a base driving circuit according to the one embodiment of the present invention.

Referring to Figs. 1A through 1C, Fig. 2 and Fig. 3, the reference numeral 1 designates a motor controlling microcomputer (hereinafter simply referred to as "MPU(A)"; 2 designates a read only memory (ROM); 3 designates a random access memory (RAM); 4 designates a programmable timer (PTM); 5 designates a base driving circuit; 6 designates a microcomputer (hereinafter simply referred to as "MPU(B)" for sending/receiving an input/ output signal between an elevator control apparatus 9 and an element such as the MPU(A) 1 or the like in a door control circuit 22; 7 designates a data bus for transmitting signals among the MPU(A) 1, the ROM 2, the RAM 3, the PTM 4, the base driving circuit 5, and the MPU(B) 6; 20 designates a door driving DC motor; 10 and 11 designate door opening driving elements for controlling the drive of the motor 20 in the door opening direction, the driving elements being constituted by transistors, IGBTs, or the like to thereby connect the motor 20 to a DC power source PN on a cage without using any other opening/closing means; 12 and 13 designate door closing driving elements for driving the motor 20 in the door closing direction; 14 through 17 designate diodes connected in an anti-parallel relation to the driving elements 10 through 13 respectively; 20a and 20b designate pulleys; 20c designates a cage door; 20d designates a belt; and 21 designates an AC power source.

In the elevator control apparatus 9 in a machine room, the reference numeral 26 designates a microcomputer (hereinafter simply referred to as "MPU(D)") for controlling the whole of the elevator; and 25 designates a microcomputer (hereinafter simply referred to as "MPU(C)") for transmitting/receiving data to/from the signal transmission/reception MPU(B) 6 of the on-cage door control circuit 22 through a transmission line 24 as well as for transmitting/receiving a signal to/from the MPU(D) 26 in the elevator control apparatus 9 in the machine room. The reference numeral 31 designates a pulse-width command circuit; 32 designates a non-lap circuit; 33 designates a watch-dog timer (WDT); and 36 through 39 designate base driver amplifiers.

The one embodiment of the present invention illustrated in Figs. 1A through 1C is for controlling the opening/closing of a door by use of a DC motor. As shown in Fig. 1A, a driving circuit for driving the motor 20 by means of a DC power source obtained by rectifying the AC power source 21 is constituted by the door opening driving elements 10 and 11 and the door closing driving elements 12 and 13 without using any other mechanical switching contacts or the like. In the illustrated circuit, the motor 20 controls the driving on the door of an elevator in the opening direction or in the closing direction under the control of the driving elements 10 through 13.

As shown in Fig. 1B, the door control circuit 22 is constituted by: the MPU(A) 1 supplied with various signals including door control signals X101 and X102 from the elevator control apparatus 9 through a signal line 23 so as to control the operation of the whole of the door control circuit 22; the ROM 2; the RAM 3; the PTM 4; and the base driving circuit 5 for producing signals OP1, OP2, CL1, and CL2 for controlling the driving elements 10 through 13 in the circuit for driving the motor 20. The door control circuit 22 is further provided with the transmission microcomputer MPU(B) 6 for transmitting/ receiving signals including a door opening forbidding signal to/from the elevator control apparatus 9 in the machine room through a transmission line 24.

Fig. 1C shows the configuration of the cage door driving mechanism for driving a cage by means of the motor 20 controlled by the door control circuit 22.

The cage door driving mechanism is constituted by the pulley 20a which is driven to rotate by means of the motor 20, the idle pulley 20b paired with the pulley 20a, and the belt 20d entrained around the pulleys 20a and 20b and connected to the cage door 20c.

This one embodiment of the present invention has a feature in that when the transmission microcomputer MPU(B) 6 receives a predetermined signal (the door opening forbidding signal) 8 from the elevator control apparatus 9 through the transmission line 24, the transmission microcomputer MPU(B) 6 supplies this signal 8 for forbidding the output of the control signal on the door opening side directly to the base driving circuit 5.

Fig. 2 shows the state in which a signal is transmitted/received between the door control circuit 22 and the elevator control apparatus 9. Referring to Fig.

2, the flow of signals related to the opening/closing of the door will be described hereunder.

The door closing signal X101 and the door opening signal X102 which are produced from the MPU(D) 26 for controlling the whole of the elevator are directly supplied to the door controlling MPU(A) 1 through the signal lines 23 connecting the elevator control apparatus 9 provided in the machine room and the door control circuit 22 provided on the cage. Further, an elevator stoppage signal X10 and a door opening/closing allowing zone signal 102F, which are shown in general as the signal 8 in Fig. 1B, allow the door to be opened when the respective levels of both the signals X10 and 102F are "H", while forbid the door to be opened when the level of either one of the signals X10 and 102F is "L". The signals X10 and 102F may be called a door opening allowing signal or a door opening forbidding signal.The signal 8, or the signals X10 and 102F, are supplied to the door control MPU(A)1 and the base driving circuit 5 through the signal transmission/reception MPU(C) 25 in the elevator control apparatus 9, the signal transmission/reception MPU(B) 6 in the door control circuit 22, and the transmission line 24. Being supplied with a non-lap signal NLP and a pulse-width signal PWM which are produced from the door controlling MPU(A) 1, the base driving circuit 5 amplifies those signals to a level so that those signals can control the door opening control elements 10 and 11 and the door closing control elements 12 and 13. The motor 20 is driven by those control elements to thereby control the opening/closing of the door of the elevator.

Fig. 3 illustrates the base driving circuit 5 in detail. Referring to Fig. 3, the base driving circuit 5 will be described in detail hereunder.

The base driving circuit 5 is constituted by the pulse-width command circuit 31, the non-lap circuit 32, the WDT circuit 33, a resistor (R) 34, the base drivers (BDC(A) through BDC(D)) 36 through 39, a power source (E) 35 for driving the base drivers BDC(A) 36 through BDC(D) 39, and a plurality of logic gates for generating signals for controlling the BDC(A) 36 through BDC(D) 3 on the basis of the respective output signals of the BDC(A) 36 through BDC(D) 39, the elevator stoppage signal X10, and the door opening/closing allowing zone signal 102F.

The BDC(A) 36 and the BDC(B) 37 supply base driving signals OP1 and OP2 to the door opening control elements 10 and 11 respectively, while the BDC(C) 38 and the BDC(D) 39 supply base driving signals CL1 and CL1 to the door closing control elements 12 and 13 respectively.

Only when an "H"-level signal is supplied to respective one terminals 1 of the BDC(A) 36 and the BDC(B) 37, the BDC(A) 36 and the BDC(B) 37 produce the signals OP1 and OP2 for performing the on-off control in accordance with PWM pulse trains supplied to the respective other terminals 2 of the BDC(A) 36 and BDC(B) 37 to drive the door opening control elements 10 and 11 so that the motor 20 can be driven to rotate in the door opening direction.

In the base driving circuit 5 having such a configuration as described above, both the respective levels of the signals WDC and WDT of the WDT circuit 33 are "L" in a normal state of the driving circuit 5, while are "H" in an abnormal state of the same. If both the respective levels of the signals WDC and WDT are made to be "H" in an abnormal state of the base driving circuit 5, the MPU(A) 1 stops to output an signal PWM because of the "H" level of the signal WDC. Accordingly, the level of a signal PWS of the pulse-width command circuit 31 becomes "H", so that the level of a signal SVP becomes "L" to indicate the abnormality. Further, the non-lap circuit 32 makes the respective levels of its output signals NLPO and NLPC "L".

Accordingly, in the case where the base driving circuit 5 is abnormal, the respective levels of a signal BSO supplied to the respective other terminals of BDC(A) 36 and the BDC(B) 37 and a signal BSC supplied to the respective other terminals of the BDC(C) 38 and the BDC(D) 39 are kept "H", so that the BDC(A) 36 through the BCD(D) 39 stop the generation of their output signals so as to stop the door control.

The operation at the time when the WDT circuit 33 indicates that the base driving circuit 5 is normal will be described hereunder.

The level of the elevator stopping signal X10 becomes "L" when the elevator is stopped, and then the level of the door opening allowing zone signal 102F becomes "H" when the position of the cage comes into the zone in which the door is allowed to open. These signals are supplied from the MPU(C) 25 of the elevator control apparatus 9 to the MPU(A) 1 through the MPU(B) 6. In this state, the MPU(A) 1 becomes able to produce a command for making the PWM signal be in the door opening direction. The PWM signal is outputted as the signal PWS from the pulse-width command circuit 31. The signal PWS makes the signals BSO at the other input terminals of the door opening base drivers BDC(A) 36 and BDC(B) 37 be pulse-width-controlled signals through gate circuits respectively. Accordingly, the door opening base drivers BDC(A) 36 and BDC(B) 37 perform door opening control.

However, if the door opening forbidding signal 8 is generated, that is, if the level of the elevator stoppage signal X10 becomes "H" or the level of the door opening allowing zone signal 102F becomes "L", the microprocessor MPU(A) 1 for generating the PWM signal is forbidden from producing the PWM signal in the door opening direction. Further, in the base driving circuit 5, the level of the signal X10 becomes "H" or the level of the signal 102F becomes "L", so that the level of the signal BSD of the one terminal 1 of each of the door opening base drivers BDC(A) 36 and BDC(B) 37 becomes "L".

As a result, the condition that the door opening base drivers BDC(A) 36 and BDC(B) 37 are forbidden from door opening control is established, so that it becomes impossible for the door opening base drivers BDC(A) 36 and BDC(B) 37 to output signals for controlling the elevator door in the opening direction. Thus, owing to the generation of the door opening forbidding signal 8, the pulse output is forbidden doubly by the PWM-pattern generating MPU(A) 1 and the base driving circuit 5.

Since the one embodiment of the present invention has such a configuration as described above, the level of the signal BSD is not become "H" so that the door opening base drivers BDC(A) 36 and BDC(B) 37 can not output the signal for controlling the drive of the door in the opening direction and the door of an elevator never opens even if the MPU(A) 1 erroneously generates a door opening command in the case where the elevator is not yet stopped, or in the case where a cage is out of the zone in which the door is allowed to open.

Although the signals X10 and 102F are supplied from the MPU(D) 26 of the elevator control apparatus 9 to the door control circuit 22 through the signal transmission/reception MPU(C) 25 and MPU(B) 6, the state of the received signal is fed back to the elevator control MPU(D) 26 through the signal transmission/ reception MPU(B) 6 and MPU(C)25 so as to be checked in the MPU(D) 26 in order to make the reliability of the signal sure.

As described above, according to this one embodiment of the present invention, the signal for forbidding opening of the elevator door is supplied to the door control microcomputer and the base drivers, so that the operation of the base drivers is surely forbidden in the state in which the door should not be opened. Thus, the door can be more surely prevented from being opened even if abnormality happens in any position, and a safety door control apparatus can be obtained.

Figs. 4A through 4C are block diagrams showing the configuration of the whole of another embodiment of the present invention. Fig. 5 is a block diagram showing the configuration of a base drive circuit in the other embodiment of the present invention. The other embodiment of the present invention is an example of the case where an induction motor is used as an electric motor for driving a door and the control of the induction motor is performed by an inverter. In Figs. 4A through 4C and Fig. 5, the reference numeral 40 designates a three-phase base driving circuit, 41 through 46 designate driving elements, 47 through 52 designate diodes connected in anti-parallel to the driving elements 41 through 46 respectively, 60 designates a three-phase induction motor, 61 designates a pulse-width command circuit, 62 designates a non-lap circuit, and 63 through 68 designate base drivers.The other reference numerals in Figs. 4A through 4C and Fig. 5 designate parts the same as those in Figs. 1A through 1C, and Figs. 2 and 3.

In the other embodiment of the present invention shown in Figs. 4A and 4B, the driving elements 41 through 46 constitute a PWM inverter so that the driving elements 41 through 46 are controlled to be turned on/off in accordance with PWM signals supplied to the respective bases thereof to thereby convert a direct current supplied across terminals P and N into a three-phase alternating current to thereby drive the induction motor 60 to rotate. The three-phase base driving circuit 40 produces signals B1 through B6 for ON-OFF control of the driving elements 41 through 46 respectively.The illustrated other embodiment of the present invention is a control system having a mechanism such that the door opening/closing control is enabled only in the condition that an elevator is in a stopped state and is in the zone in which the door is allowed to open, while in other conditions braking force is produced to make the door not to be easily opened mechanically.

As the above driving elements 41 through 46, for example, IGBTs, MOSFETs, bipolar transistors, or the like, may be used, those elements being switchingcontrolled with a frequency which is higher beyond an audible band.

Fig. 4C shows the configuration of an example of a mechanism for making a cage door driving mechanism, which drives a door by means of the motor 60 under the control by the door control circuit, have mechanical force.

In the cage door driving mechanism, a cage door 20c is driven so as to open/close by rotational force of the induction motor 60 through pulleys 60a, 60b, and 60c and a link 60e. Points A and B in the drawing are fulcrums fixed to the door 20c and a wall of a building respectively. As the pulley 50c is rotated, the link 60e is rotationally moved to thereby horizontally move the case door 20c along a guide rail 60f.

Fig. 4C shows the state in which the cage door 20c is in its closed state. In this state, a weight 60d attached to the pulley 60c gives force in the closing direction to the cage door 20c by means of the weight thereof.

Although the base driving circuit 40 is different from the base driving circuit described in Fig.

3 in the points that the pulse-width command circuit 61 and the non-lap circuit 62 are arranged so as to be used in a three-phase fashion, and the base drivers in six pairs are provided so as to be able to control the three-phase inverter as described in detail in Fig. 5, the other configuration of the base driving circuit 40 is substantially the same as that in the case of Fig. 3.

In Fig. 5, on the basis of a signal produced from the MPU(A) 1, the pulse-width command circuit 61 generates three-phase pulse-width signals PWU, PWV, and PWW and the non-lap circuit 62 generates three-phase non-lap signals NLPul, NLPu2, NLPv1, NLPv2, NLPwl, and NLPw2.

When the base driving circuit 40 is normal, the respective levels of both the signals WDC and WDT produced from the WDT circuit 33 are "L". When "L" level signals are produced from the pulse-width command circuit 61 as the signals PWU, PWV, and PWW having pulse widths corresponding to respective phases, the signals PWu, PWv, and PWw passed through the gate circuits become inverted signals which have the same pulse widths as those of the signals PWU, PWV, and PWW respectively and which have levels of "H" respectively, because the level of the signal WDT is "L".

On the other hand, in accordance with the respective phases, the non-lap circuit 62 makes the respective levels of the signals NLPul, NLPu2, NLPvl, NLPv2, NLPwl, and NLPw2 "H" so as to assure the non-lap time between up and down arms of the inverter.

Accordingly, the respective levels of signals BS1 through BS6 to be supplied to the respective other input terminals of the base drivers BDC(A) 63 through BDC(F) 68 become "H" succeedingly so that a three-phase alternating current is generated.

Further, in the case where an elevator is in its stopped state and is in the zone in which the door is allowed to open, the level of the elevator stoppage signal X10 becomes "L", while the level of the door opening allowing zone signal becomes "H". As a result, the level of a signal BSD at the respective one input terminals of the base drivers BDC(A) 63 through BDC(F) 68 becomes "H". As a result, the base drivers BDC(A) 63 through BDC(F) 68 are enabled to produce output signals B through B6 succeedingly. The output signals B1 through B6 control ON/OFF of the driving elements 41 through 46 so that a three-phase output voltage is supplied to the induction motor 60 so as to control the rotation of the induction motor 60.

According to the other embodiment of the present invention, even if a door opening signal is produced in spite of the conditions in which the door opening forbidding signal exists, that is, an elevator is not in its stopped state or the cage is not in the zone in which the door is allowed to open, the level of the signal BSD to be supplied to the respective one input terminals 1 of the base drivers BDC(A) 63 through BDC(F) 68 is "L" so that the base drivers BDC(A) 63 through BDC(F) 68 can not produce output signals B1 through B6 respectively. As a result, the three-phase output voltage is kept zero, so that the induction motor 60 is not rotated and the door cannot be opened. Thus, both the control-signal generating microprocessor 1 and the base driving circuit 40 doubly perform the forbidding operation by means of the door opening forbidding signal 8.

As described above, according to the one and other embodiments of the present invention, it is possible to provide the safe door control apparatus in which a predetermined state signal indicating forbidding of opening of an elevator door is supplied to the door control microcomputer and the base driving circuit for controlling the driving elements so as to forbid the door opening operation doubly, so that the door can be prevented from being opened in the case where the elevator is not in its stopped state, in the case where a cage is not in the zone in which the door is allowed to open, or in the case where a fault occurs in the elevator.

As described above, according to the present invention, an improvement in safety of an elevator door control apparatus can be expected, by a simple but highly reliable configuration, by supplying a signal for forbidding opening of an elevator door to both a door controlling microcomputer and a door motor control circuit controlled by the computer.

Claims

1. An elevator apparatus comprising: an electric motor for driving a door of an elevator; semiconductor control elements for controlling electric power to be supplied to said motor; a driving circuit for generating a control signal to be supplied to said semiconductor control elements, on the basis of a door opening/closing command from an elevator control means; and means for preventing a control signal for opening said door from being supplied from said driving circuit to said semiconductor control elements, in accordance with a predetermined signal supplied from said elevator control means.

2. An elevator apparatus comprising: an electric motor for driving a door of an elevator; semiconductor control elements for controlling electric power to be supplied to said motor; a pattern generating means for generating an on-off pattern for said semiconductor control elements on the basis of a door opening/closing command from an elevator control means; a driving circuit supplied with said on-off pattern and for generating a control signal to be supplied to said semiconductor control elements; and means for preventing respective outputs of said pattern generating means and said driving circuit, in accordance with a predetermined signal supplied from said elevator control means.

3. An elevator apparatus comprising: an electric motor for driving a door of an elevator; semiconductor control elements connected between a DC power supply and said motor without interposition of any mechanical circuit-opening/closing means and for controlling electric power supplied to said motor; a pattern generating means for generating an on-off pattern for said semiconductor control elements on the basis of a door opening/closing command from an elevator control means; a driving circuit supplied with said on-off pattern and for generating a control signal to be supplied to said semiconductor control elements; and means for preventing respective outputs of said on-off pattern for opening said door and said control signal for opening said door, in accordance with a predetermined signal for forbidding the opening of said door supplied from said elevator control means.

4. An elevator apparatus comprising: a DC motor for driving a door of an elevator; opening/closing control elements for driving said motor; a driving circuit for driving said opening/closing control elements; a microcomputer for supplying said driving circuit with a command for opening/closing said door; and an elevator control means for supplying said microcomputer with a command for opening/closing said door; said opening/closing control elements including door opening driving elements for driving said door in the door opening direction, and door closing driving elements for driving said door in the door closing direction; and said microcomputer and said driving circuit respectively include means for preventing the respective outputs thereof in the door opening direction in accordance with a predetermined signal supplied from said elevator control means to said microcomputer and said driving means respectively.

5. An elevator apparatus according to Claim 4, further comprising means for causing said door closing driving elements to continuously control said DC motor when said door is in a fully closed state.

6. An elevator apparatus comprising: an induction motor for driving a door of an elevator; semiconductor control elements for controlling electric power to be supplied to said motor, said semiconductor control elements constituting an inverter; a driving circuit for generating a control signal to be supplied to said semiconductor control elements, on the basis of a door opening/closing command from an elevator control means; and means for preventing said control signal from being supplied from said driving circuit to said semiconductor control elements, in accordance with a predetermined signal from said elevator control means.

7. An elevator apparatus comprising: an induction motor for driving a door of an elevator; semiconductor control elements for controlling electric power to be supplied to said motor, said semiconductor control elements constituting an inverter; a driving circuit for generating a control signal to be supplied to said semiconductor control elements, on the basis of a door opening/closing command from an elevator control means; means, other than said induction motor, for adding a door opening force when said door is in a fully closed state; and means for preventing said control signal from being supplied from said driving circuit to said semiconductor control elements, in accordance with a predetermined signal supplied from said elevator control means.

8. An elevator apparatus comprising: an electric motor for driving a door of an elevator; a power converter for controlling electric power to be supplied to said motor; means for controlling said power converter on the basis of a door opening/closing command so as to drive said motor in a forward/reverse direction; a transmission microcomputer provided on a cage for transmitting/receiving a signal to/from an elevator control means provided in a machine room; and means for preventing said converter control means from operating, in accordance with a predetermined signal received by said transmission microcomputer.

9. An elevator comprising: an electric motor for driving a door of an elevator; a power converter provided on a cage for controlling electric power to be supplied to said motor, said power converter being arranged to connect a power supply provided on said cage to said motor without interposition of any other mechanical circuitopening/closing means; means for controlling said power converter to drive said motor in accordance with a door opening/ closing command; and a transmission means provided on said cage for transmitting/receiving a signal to/from an elevator control means provided in a machine room; and means for making said converter control means stop by a predetermined signal from said transmission signal.

10. A main circuit apparatus for driving an elevator door, comprising: a motor for driving said elevator door; and a semiconductor power converter connected between said motor and a power supply input terminal without interposition of any other mechanical circuitopening/closing means.

11. An elevator apparatus comprising: an electric motor for driving a door of an elevator; a power converter for controlling electric power to be supplied to said motor; a converter control means for controlling said power converter so as to drive said motor on the basis of a door opening/closing command; a first transmission means through which said door opening/closing command is transmitted from an elevator control means provided in a machine room; a second transmission means disposed between a cage and said elevator control means provided in said machine room; and means for forbidding at least a door opening direction output of said converter control means in accordance with a predetermined signal supplied from said second signal transmission means.